Porting another 350

[isaaccarlson]

Here are the numbers from before and after the mods, but the saw is not fully assembled yet.

Before After

Comp 120 Comp ???
Squish .050 Squish .019

Intake 73* Intake 74*
Exhaust 106* Exhaust 104
Transfers 133* Transfers 123

Blowdown 27* Blowdown 19*

I wanted to keep a bit more blowdown, but it’s real close. The intake duration is a bit long for me, but we’ll see how it runs. I like to keep the intake duration shorter with a bigger port so I can pack as much mix in there as possible, but these transfers should make up for some of that. Everything is chamfered, and ready to go. The only things left are to clean the saw chassis, shorten the cylinder bolts, and open the muffler. The remaining parts are getting close!

 

[isaaccarlson]

Ok, the parts are in. Now it’s time to put this thing together! I just need to find my tube of sealant.....
I should be able to get it put together in the next few days. I have a new clutch, rim sprocket, air filter, bearings, seals, etc...
I can’t wait to get it in some wood.

 

[isaaccarlson]

The saw is together and it runs great. The test run yesterday was a flop because my old tube of sealer went bad and the fuel ate the sealer and it gummed up the inside of the motor, almost ruining it. I tore it down right away, cleaned everything up, and put it back together with some new sealant (thanks @Mastermind , I could not get dirco right away, so I used motoseal).

I let it sit 24 hours before starting. It runs strong and I can lean on it pretty hard. We are having a thunderstorm right now, so no video yet, but I will get some. It winds out pretty good and I’m happy with the way it turned out. The exhaust is as wide as it can go and has a trapezoid shape. I didn’t go crazy with the intake, just widened it a bit. I spent most of my time on the transfers. They are just plain huge and look nothing like they used to. I also removed a ton of material from the piston. I am pretty sure it will hold up, but time will tell. I think 10 or 12 tanks should be enough time to see if it lets go. If this saw stays together, this is my new recipe.

Squish is .019 and compression after assembly was 160. I will check it again after a few tanks. Blowdown is 19* exhaust is 104* and intake is 74*. I did the build the way I did to test a new recipe and see what it would do. No popup, carb work, or machining, just hand tools and some time. It’s easy to tune and idles well. It pulls chips and noodles like nobody’s business. No complaints here.

 

[isaaccarlson]

I have about a tank of mix through it so far, and it’s only running stronger. It’s hard to put a load on it, it just keeps pulling. I let my brother run it, and he thought he would make a few speed cuts with it. The down cut was fine, but the up cut pushed him back about a foot. I really like this saw. I’d be happy to find another one to build.

I completely forgot to take pictures of the saw before assembly, and I’m not tearing it apart again unless something goes horribly wrong.

 

[isaaccarlson]

I’m wishing I had pictures of the inside of this saw. It gets stronger every time I use it. I took a good bit off the rakers and it still hauls the mail with the bar burried in oak. It’s a torquey critter for sure. I will try to get a log set up for some video action in the next few days. I have been busy working on saws for other folks, so I haven’t had a ton of time to set up a camera and make a batch of cookies.